Improving the complexing properties of fibers allows different active compounds such as fragrances, insecticides, bactericidal agents, antistatic agents, anti-bacterial agents or repellent agents to be adsorbed onto a fiber or fiber-based material. Because the adsorbed active product subsequently diffuses into the surrounding atmosphere (release), the complexing phenomenon, which occurs in the fibers, endows the fiber or any material containing it with the different chemical properties of the adsorbed product for a set period that depends on the rate of diffusion of the complexed product (release rate).
One known method for improving the adsorbent properties of a fiber is fixing (grafting) molecules of cyclodextrin(s) onto the fiber.
Cyclodextrins (α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin) have long been known to be molecules possessing complexing properties, i.e., molecules that are capable of reversibly trapping certain other small molecules of a hydrophobic nature, in particular aliphatic or aromatic molecules, from their solutions, vapors or solid mixtures. The adsorbed molecules are bonded to the cyclodextrin by the formation of inclusion complexes.
The release rate of the product complexed by cyclodextrins is small, so fibers functionalized by cyclodextrins are perfectly suited to produce fiber-based materials, in particular textiles, which possess the chemical properties of the complexed product in a stable manner and for long periods, and also to produce adsorbent materials. These adsorbent materials have a number of applications, in particular in water purification and contaminated gas purification.
Textile materials functionalized with cyclodextrins with adsorbed fragrances, antistatic agents, antimicrobial agents, insect repellents, bactericidal agents, or insecticides, have been respectively described in the following documents: Japanese patent JP-A-06-116871, U.S. Pat. No. 5,376,287, JP-A-09 315920, JP-A-04-263617, JP-A-09-228144, JP-A-05-311509, U.S. Pat. No. 5,670,456 and JP-A-03-59178.
Textile materials functionalized by cyclodextrins and with hygroscopic and odor adsorption properties have been described in JP-A-06-322670, JP-A-02-127573, JP-A-03-14678, JP-A-08-199478, JP-A-02-251681 and JP-A-163372.
Textiles functionalized with cyclodextrins and used as adsorbents, in particular as barriers to contaminants, have been described in U.S. Pat. No. 5,776,842.
These examples are not limiting. Potential applications for textiles functionalized with cyclodextrins have been cited by Denter and Schollmeyer in the document “Proceedings of the Eighth International Symposium on Cyclodextrins”, Budapest, Hungary, 1996, J. Szejtli and L. Szente Eds, Kluwer Academic Publishers.
The principal technical difficulty in producing fibers and textiles functionalized by cyclodextrins or their inclusion complexes is to fix molecules of cyclodextrin(s) or their inclusion complexes onto fibers and textile materials in a durable manner. A number of fixing methods has been developed.
U.S. Pat. No. 4,357,468 describes a method for fixing cyclodextrin(s) using epichlorhydrin.
European patent EP-A-0 697 415, German patent DE-A-19520967 and Denter U., Schollmeyer E., J. Inclusion Phenom. Mol. Recognit. Chem. 25(1–3), 197–202 (1996) describe a method for fixing cyclodextrins using chlorinated heterocyclic compounds.
EP-A-0 488 294 and JP-A-03-59178 disclose a fixing method using reactive aminosiloxanes and siloxanes.
U.S. Pat. No. 5,098,793 describes polymers obtained by reacting cyclodextrin with an activated dicarboxylic acid. Such polymers form a film that adheres to the surface of a substrate that can be a cellulose substrate, for example. They do not contain any residual carboxylic acid functions because they come from dicarboxylic acid and since both of its carboxylic acid functions have been reacted.
JP-A-06-322670 describes a fixing method using a resin based on an aminosilicone and/or polyurethane.
JP-A-02—127573 describes a fixing method using a polymer (Hercosett 57) obtained by cross-linking a polyamide with epichlorhydrin.
JP-A-09-228144 describes a fixing method by incorporating cyclodextrins or their inclusion complexes into the chemical fiber spinning dope.
Finally, DE-A-4035378 describes a method for fixing cyclodextrin(s) or cyclodextrin derivative(s) using reactants carrying dimethylol urea groups or derivatives of such groups that react both with a hydroxyl group of the cyclodextrin and with a functional group of the fiber, bonding the cyclodextrin molecule to the fiber.